Index: core/install/install_toolkit.php
===================================================================
--- core/install/install_toolkit.php
+++ core/install/install_toolkit.php
@@ -96,7 +96,14 @@
 		 */
 		var $_installator = null;
 
-		function kInstallToolkit()
+		/**
+		 * True when module installing from admin console.
+		 *
+		 * @var boolean
+		 */
+		protected $isSeparateModuleInstall;
+
+		function kInstallToolkit($is_separate_module_install = false)
 		{
 			$this->defaultWritablePath = DIRECTORY_SEPARATOR . 'system';
 
@@ -111,6 +118,7 @@
 			$this->INIFile = FULL_PATH . $this->defaultWritablePath . DIRECTORY_SEPARATOR . 'config.php';
 
 			$this->systemConfig = $this->ParseConfig(true);
+			$this->isSeparateModuleInstall = $is_separate_module_install;
 		}
 
 		/**
@@ -438,7 +446,8 @@
 			$language_import_helper = $this->Application->recallObject('LanguageImportHelper');
 			/* @var $language_import_helper LanguageImportHelper */
 
-			$language_import_helper->performImport($lang_file, '|0|1|2|', '', $upgrade ? LANG_SKIP_EXISTING : LANG_OVERWRITE_EXISTING);
+			$import_mode = $upgrade || $this->isSeparateModuleInstall ? LANG_SKIP_EXISTING : LANG_OVERWRITE_EXISTING;
+			$language_import_helper->performImport($lang_file, '|0|1|2|', '', $import_mode);
 		}
 
 		/**
Index: modules/custom/install.php
===================================================================
--- modules/custom/install.php
+++ modules/custom/install.php
@@ -16,7 +16,7 @@
 		require_once $constants_file;
 	}
 
-	$toolkit = new kInstallToolkit();
+	$toolkit = new kInstallToolkit(true);
 }
 else {
 	// install, using installation wizard
@@ -35,4 +35,4 @@
 $toolkit->RunSQL('/' . $module_folder . '/install/install_data.sql');
 $toolkit->ImportLanguage('/' . $module_folder . '/install/english');
 
-$toolkit->finalizeModuleInstall($module_folder, false);
\ No newline at end of file
+$toolkit->finalizeModuleInstall($module_folder, false);
Index: modules/in-bulletin/install.php
===================================================================
--- modules/in-bulletin/install.php
+++ modules/in-bulletin/install.php
@@ -28,7 +28,7 @@
 		require_once $constants_file;
 	}
 
-	$toolkit = new kInstallToolkit();
+	$toolkit = new kInstallToolkit(true);
 }
 else {
 	// install, using installation wizard
Index: modules/in-commerce/install.php
===================================================================
--- modules/in-commerce/install.php
+++ modules/in-commerce/install.php
@@ -27,7 +27,7 @@
 		require_once $constants_file;
 	}
 
-	$toolkit = new kInstallToolkit();
+	$toolkit = new kInstallToolkit(true);
 }
 else {
 	// install, using installation wizard
Index: modules/in-link/install.php
===================================================================
--- modules/in-link/install.php
+++ modules/in-link/install.php
@@ -28,7 +28,7 @@
 		require_once $constants_file;
 	}
 
-	$toolkit = new kInstallToolkit();
+	$toolkit = new kInstallToolkit(true);
 }
 else {
 	// install, using installation wizard